Online measurement method for multi-type mixed particle mass concentration

Abstract

The invention belongs to the technical field of environmental monitoring, and discloses an online measurement method for multi-type mixed particle mass concentration, the method comprises the following steps: 1) establishing a database of particle wavelength scattering correlation coefficients; 2) placing a multi-type mixed particle into a light scattering measuring device, and using the light scattering measuring device to measure to obtain scattered light intensities generated by the multi-type mixed particle at m wavelengths; and 3) transmitting scattered light intensity signals measured bythe light scattering measuring device to a central workstation, and using the central workstation to obtain the mass concentration of each particle in the multi-type mixed particle according to the scattered light intensities obtained in the step 2) and the database of the particle wavelength scattering correlation coefficients obtained in the step 1). The method is based on the difference of light scattering caused by particle types, realizes the classification measurement of the particle types, overcomes the influence of the particle types on the mass concentration measurement of the particles, and improves the measurement precision of the mass concentration of the particles.

Description

technical field [0001] The invention belongs to the technical field of environmental monitoring, and more particularly relates to an online measurement method for the mass concentration of multi-type mixed particulate matter. Background technique [0002] In the process of environmental particle monitoring, the measured particles are usually a mixture of multiple types of particles; for example, aerosols are generally divided into sand and dust aerosols, carbon aerosols, inorganic salt aerosols, etc. The measured aerosol is a combination of various types of aerosols, and its particle mass concentration and particle type parameters are important data for environmental monitoring. [0003] At present, the mass concentration detection methods of particulate matter usually include weighing method, light scattering method, light transmission method, β-ray method, charging method, etc.; weighing method and β-ray method are based on the quality difference of the filter membrane bef...

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Problems solved by technology

[0003] At present, the mass concentration detection methods of particulate matter usually include weighing method, light scattering method, light transmission method, β-ray method, charging method, etc.; weighing method and β-ray method are based on the quality difference of the filter membrane before and after a measurement period to obtain the particulate matter in the measurement period. Average mass concentration, but its measurement accuracy is limited by the cycle time. The longer the cycle, the higher the measurement accuracy, and it is difficult to achieve real-time measurement. It is usually used as a calibration method for particle mass concentration measurement; light transmission method (also known as turbidity method) is based on the laser passing through The extinction ratio behind the particles is used to determine the particle mass concentration, but only when the extinction is between 30% and 70% can it have high accuracy, and there will be a large measurement error at low concentrations, which is difficult to meet the needs of low concentration measurements; The electric method is to charge the particulate matter first, then measure the induced current, and determine the mass concentration of the particulate matter according to the magnitude of the induced current, but this method is affected by the uncertain factor air flow velocity, and the measurement results fluctuate greatly; the light scattering method is based on a certain solid angle The scattered light of the dust particles collected inside, the particle mass concentration is obtained according to the proportional relationship between the scattered light intensity and the volume concentration of dust particles, which is suitable for the measurement of low concentration particles

[0004] Among the above measurement methods, the light scattering method is widely used due to its advantages of high sensitivity, fast response speed, wide range of adaptability to concentration and non-invasive measurement. However, the scattered light is not only affected by the mass concentration of particles, but also by the characteristics of particles If the influence of the particle's own characteristics is not considered, it will usually cause inestimable errors in the measurement results

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